4,138 research outputs found
Laser-Assisted Synthesis of Non-Equilibrium Nanoalloys
No full textVincenzo Amendola is Professor of Physical Chemistry at Padova University, where he established and directs the Laser-Assisted Synthesis and Plasmonics (LASP) lab. He obtained a PhD in Materials Science and Engineering in 2008 and the Italian qualification as Full Professor in 2017, after research experience at Massachusetts Institute of Technology and Cambridge University. He is part of the Program Committee of the ANGEL conference series and he is a current member of the ChemPhysChem Editorial Advisory Board
SINTESI MEDIANTE ABLAZIONE LASER IN SOLUZIONE E MANIPOLAZIONE DI NANOPARTICELLE METALLICHE PER APPLICAZIONI IN FOTONICA
No full textLe nanoparticelle (Np) di oro e argento hanno un ruolo importante nelle nanotecnologie, per via delle loro proprieta’ plasmoniche, della loro stabilita’ chimica e della facilita’ con cui si funzionalizza la loro superficie. La sintesi per ablazione laser in soluzione (LASiS – Laser Ablation Synthesis in Solution) rappresenta una tecnica semplice, versatile e rapida per ottenere Np di metalli nobili in acqua o in solventi organici, senza la necessita’ di inserire stabilizzanti o altri reagenti chimici.1 La dimensione delle Np ottenute mediante LASiS puo’ essere ulteriormente modificata attraverso tecniche laser “chemical free” ispirate ad approcci “top down” e “bottom up”.2 Questo consente la funzionalizzazione in “one step” delle particelle per semplice aggiunta dei leganti di interesse, con risparmio di reagenti chimici e l’assenza di rifiuti rispetto alle tradizionali sintesi per riduzione chimica. Inoltre la spettroscopia UV – visibile consente di ricavare informazioni sul ricoprimento con leganti e di stimare le dimensioni medie, la concentrazione e l’aggregazione delle particelle. Le Np di oro ottenute mediante LASiS sono state utilizzate per studi di assorbimento ottico non lineare, di terapia fototermica in cellule tumorali e di modulazione delle proprieta’ di cristalli fotonici.3
1 V. Amendola, S. Polizzi, M. Meneghetti; J. Phys. Chem. B 2006, 110, 7232 – 7237; V. Amendola, S. Polizzi, M. Meneghetti; Langmuir 2007, 23, 6766 – 6770; V. Amendola, G. A. Rizzi, S. Polizzi, M. Meneghetti; J. Phys. Chem. B 2005, 109, 23125 – 23128.
2 V. Amendola, M. Meneghetti; J. Mater. Chem. 2007, 17, 4705-4710.
3 V. Amendola, S. Polizzi, K. Kadish, D. Dini, M. Hanack, M. Meneghetti; Submitted; S. Salmaso, P. Caliceti, V. Amendola, M. Meneghetti, G. Pasparakis, A. Cameron; Submitted; V. Morandi, F. Marabelli, V. Amendola, M. Meneghetti, D. Comoretto; Adv. Func. Mater. 2007, 17, 2779–2786
Plasmonic characterization and photonic applications of noble metal nanoparticles obtained by LASiS
No full textNoble metal nanoparticles (NMNPs) are powerful tools in modern nanotechnology, thanks to their peculiarities: the intense surface plasmon resonance (SPR), the chemical stability and the simple surface chemistry. Many authors showed that laser ablation synthesis in solution (LASiS) is a viable and versatile technique for obtaining colloidal solutions of NMNPs.[1]
NMNPs can be precisely characterized in situ by UV-visible spectroscopy with the aid of the Mie theory, providing informations about the size, aggregation level and dielectric environment of particles obtained by LASiS.[2-5] Moreover, the ability of obtaining NMNPs free in solution by LASiS allows the real time monitoring of surface functionalization by UV-visible spectroscopy.[6,7]
Plasmon properties of NMNPs obtained by LASiS were exploited for a series of photonic applications: i) sodium dodecylsulphate coated gold nanoparticles (AuNPs) were used for linear and nonlinear optical modulation of the photonic band gap in artificial opals;[8,9,10] ii) unprotected gold nanoparticles blended with zinc phthalocyanines showed efficient optical limiting due to the strong multiphoton absorption properties of AuNPs and to the self healing of photofragmented nanoparticles that is promoted by phthalocyanines under laser irradiation;[11,12] iii) AuNPs conjugated with a thermoresponsive polymer were used for temperature triggered uptake in cancerous cells and were studied for photothermolysis of cancerous cells by laser irradiation;[6] iv) ultrabright surface enhanced Raman scattering labels based on NMNPs conjugated with organic dyes and stabilized with polyethylene glycol were used for quantifying the number of nanoparticles uptaken by macrophage cells.[13]
Bibliography
[1] V. Amendola, M. Meneghetti, Phys. Chem. Chem. Phys. 2009, 11, 3805–3821.
[2] V. Amendola, M. Meneghetti, J. Phys. Chem. C 2009, 113, 4277–4285.
[3] V. Amendola, S. Polizzi, M. Meneghetti; Langmuir 2007, 23, 6766 – 6770.
[4] V. Amendola, S. Polizzi, M. Meneghetti; J. Phys. Chem. B 2006, 110, 7232 – 7237
Bioconjugation and photonic applications of metal nanoparticles obtained by laser ablation in liquid solution
No full textMetal nanoparticles (MNP) have a notable role in nanotechnology, due to their surface plasmon absorption (SPA) and to their surface chemistry. Functionalization and/or bioconjugation are key points for MNP applications, and they depend on surface accessibility and on solvents compatibility with the functional molecules. Often, synthesis methods based on chemical reduction require long and expensive processes to obtain the desired MNP functionalization.
An alternative is represented by laser ablation synthesis of metal nanoparticles in liquid solution (LASiS).[1-3] LASiS provides stable colloidal solutions in water or in organic solvents, without any ligand or stabilizing molecule. Therefore MNP surface is usually free and functionalization occurs directly in the same solvent where MNP are obtained. These methods proved to be suitable for the conjugation in one step of MNP with a wide range of organic- and bio-molecules, also allowing the real time monitoring of the surface coverage process by UV-Vis spectroscopy. By fitting the UV-Vis spectra with a model based on the Mie theory, also the average size of MNP can be obtained with good accuracy.[1-3]
The size of MNP obtained by LASiS can be further manipulated by a chemical free laser techniques inspired by top down and bottom up approaches. Gold nanoparticles (AuNP) with average radii of 4.5 nm were obtained in this way, which allowed the sensing of AuNP bioconjugation with bovine serum albumin (BSA) down to a ratio of 10:1 for AuNP:BSA.[4]
The conjugation of AuNP with the thermo-responsive polymer poly-N-isopropylacrylamide was exploited for the temperature controlled cellular uptake of AuNP and the photothermal therapy of AuNP loaded human breast adenocarcinoma MCF7 cells.[5]
Non functionalized AuNP have been studied for nonlinear optical applications. AuNP synthesized by LASiS in water solution of sodium dodecylsuphate have been used for the optical doping of polystirene opals, which allowed the controlled red shift of the photonic pseudogap. The strong SPA of AuNP also allowed the switching of the photonic bandgap upon irradiation with 9 ns laser pulses at 532 nm.[6]
A blend of zinc phthalocyanines (ZnPc) and gold nanoparticles obtained by LASiS in tetrahydrofuran showed enhanced optical limiting properties at 532 nm (9 ns) due to a photoinduced redox mechanism between AuNP and ZnPc. This mechanism allowed the self healing of gold nanoparticles during the optical limiting measurements, though the laser induced photo-fragmentation of AuNP at the base of the limiting process.[7]
1. V. Amendola, S. Polizzi, M. Meneghetti; J. Phys. Chem. B 2006, 110, 7232 – 7237.
2. V. Amendola, S. Polizzi, M. Meneghetti; Langmuir 2007, 23, 6766 – 6770.
3. V. Amendola, G. A. Rizzi, S. Polizzi, M. Meneghetti; J. Phys. Chem. B 2005, 109, 23125 – 23128.
4. V. Amendola, M. Meneghetti; J. Mater. Chem. 2007, 17, 4705-4710.
5. S. Salmaso, P. Caliceti, V. Amendola, M. Meneghetti, G. Pasparakis, A. Cameron; Submitted.
6. V. Morandi, F. Marabelli, V. Amendola, M. Meneghetti, D. Comoretto; Adv. Func. Mater. 2007, 17, 2779–2786.
7. V. Amendola, S. Polizzi, K. Kadish, D. Dini, M. Hanack, M. Meneghetti; In preparation
SERS active gold nanostructures for selective and ultrabright biolabelling: synthesis and quantitative study
No full textSurface enhanced Raman scattering (SERS) probes based on gold nanoparticles (AuNPs) – organic dyes nanocomposites disclosed new opportunities for multiplexed ultrasensitive biolabelling in vitro or in vivo. SERS labels also have excellent biocompatibility and can be excited with near infrared laser sources, that match the transparency window of biological tissues. Here we report about the preparation of AuNPs obtained by laser ablation synthesis in solution (LASiS)[1,2] and their functionalization with a series of Raman reporter with different spectral fingerprints. The effective differential Raman scattering cross section of these labels were evaluated using liquid Raman standards and the analysis of the surface plasmon band of AuNPs with the Mie – Gans models.[3] We estimated that few (<10) SERS labels are enough to collect a clear Raman spectrum with a common Raman spectrometer. SERS labels were used for the study of nanoparticles uptake in macrophages[4] in order to quantify the number of nanoparticles phagocytized after different times. The conjugation of SERS labels with antibodies that selectively binds antigens over-expressed by specific types of cancerous cells is under investigation for the antibody – directed selective ultrasensitive detection and imaging of cancer.
[1] V. Amendola, M. Meneghetti, Phys. Chem. Chem. Phys. 2009,
[2] V. Amendola, M. Meneghetti; J. Mater. Chem. 2007, 17, 4705–4710.
[3] V. Amendola, M. Meneghetti, J. Phys. Chem. C 2009, 113, 4277–4285.
[4] V. Amendola, M. Meneghetti, S. Fiameni, G. Fracasso, A. Boscaini, M. Colombatti; Submitte
Preparation and quantitative study of gold nanoparticles forSERS biolabelling
No full textSERS probes based on gold nanoparticles – organic dyes nanocomposites are intensively investigated for in vitro and in vivo labelling or for bio-analytical applications. Their main advantages are: biocompatibility, enormous Raman scattering cross section, analysis at wavelengths in the transparency window of biological tissues, multiplex analysis based on the distinctive fingerprint of each label. Here we report about the preparation of AuNP obtained by laser ablation synthesis in solution (LASiS)1-5 and their functionalization with a series of Raman labels with different properties. The Raman scattering cross section and the minimum number of AuNP observable by Raman spectroscopy in different conditions were measured and used for quantitative comparison of the different labels. Optical microscopy and transmission electron microscopy were coupled to Raman analysis for this purpose. Calibration studies were applied to the quantification of cell uptake studies of nanoparticles. The results suggests that, in the best cases, about ten AuNP in the analysis volume are enough for practical application with common Raman spectrometers.
1 V. Amendola, M. Meneghetti, “Laser ablation synthesis in solution and size manipulation of noble metal nanoparticles”, invited Perspective Article, Phys. Chem. Chem. Phys. 2009, Accepted.
2 V. Amendola, M. Meneghetti, J. Phys. Chem. C 2009, 113, 4277–4285.
3 S. Salmaso, P. Caliceti, V. Amendola, M. Meneghetti, J. P. Magnusson, G. Pasparakis, C. Alexander; J. Mater. Chem. 2009, 19, 1608 – 1615.
4 V. Amendola, M. Meneghetti; J. Mater. Chem. 2007, 17, 4705–4710.
5 V. Amendola, S. Polizzi, M. Meneghetti; J. Phys. Chem. B 2006, 110, 7232 – 7237
La donazione di Hellmut Hager e Maria Antonietta Sportelli: una questione di ragione e sentimento
No full textL'autore ricostruisce la storia della formazione della collezione dello storico dell'arte Hellmut Hager e di sua moglie Maria Antonietta Sportelli, facendo luce su inediti aspetti che ne hanno determinato la donazione al Comune di Genzano.The author reconstructs the history of the collection of the art historian Hellmut Hager and his wife Maria Antonietta Sportelli, shedding light on previously unpublished aspects that led to its donation to the municipality of Genzano
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